Microrna-124 targets flotillin-1 to regulate proliferation and migration in breast cancer

The Role of MicroRNA-124-3p in Breast Cancer Stem Cell Inhibition by Benzyl Isothiocyanate

PURPOSE

We have shown previously that benzyl isothiocyanate (BITC) derived from cruciferous vegetables inhibits self-renewal of breast cancer stem-like cells (bCSC). The current study provides insights into the mechanism of bCSC inhibition by BITC.

METHODS

Quantitative real time-polymerase chain reaction and western blot analysis were performed to detect microRNAs (miRNAs) and Forkhead box Q1 (FoxQ1) protein expression, respectively. The bCSC were characterized by aldehyde dehydrogenase 1 activity and flow cytometric analysis of CD49f high/CD133high fraction.

RESULTS

BITC treatment resulted in induction of miR-124-3p expression in MDA-MB-231 and MCF-7 cells. miR-124-3p did not affect BITC-mediated inhibition of cell migration or cell proliferation but it significantly regulated bCSC in response to BITC. We also found that miR-124-3p directly targets the 3'untranslated regions (UTR) of FoxQ1 and negatively regulates its expression. The BITC-mediated inhibition of bCSC was partially attenuated by miR-124-3p inhibitor.

CONCLUSIONS

These findings indicate that miR-124-3p plays an important role in BITC-mediated inhibition of bCSC.

Predictive and prognostic biomarkers of bone metastasis in breast cancer: current status and future directions

The most common site of metastasis in breast cancer is the bone, where the balance between osteoclast-mediated bone resorption and osteoblast-mediated bone formation is disrupted. This imbalance causes osteolytic bone metastasis in breast cancer, which leads to bone pain, pathological fractures, spinal cord compression, and other skeletal-related events (SREs). These complications reduce patients' quality of life significantly and have a profound impact on prognosis. In this review, we begin by providing a brief overview of the epidemiology of bone metastasis in breast cancer, including current diagnostic tools, treatment approaches, and existing challenges. Then, we will introduce the pathophysiology of breast cancer bone metastasis (BCBM) and the animal models involved in the study of BCBM. We then come to the focus of this paper: a discussion of several biomarkers that have the potential to provide predictive and prognostic value in the context of BCBM-some of which may be particularly compatible with more comprehensive liquid biopsies. Beyond that, we briefly explore the potential of new technologies such as single-cell sequencing and organoid models, which will improve our understanding of tumor heterogeneity and aid in the development of improved biomarkers. The emerging biomarkers discussed hold promise for future clinical application, aiding in the prevention of BCBM, improving the prognosis of patients, and guiding the implementation of personalized medicine.

The roles of FLOT1 in human diseases (Review)

FLOT1, a scaffold protein of lipid rafts, is involved in several biological processes, including lipid raft protein‑-dependent or clathrin‑independent endocytosis, and the formation of hippocampal synapses, amongst others. Increasing evidence has shown that FLOT1 can function as both a cancer promoter and cancer suppressor dependent on the type of cancer. FLOT1 can affect the occurrence and development of several types of cancer by affecting epithelial‑mesenchymal transition, proliferation of cancer cells, and relevant signaling pathways, and is regulated by long intergenic non‑coding RNAs or microRNAs. In the nervous system, overexpression or abnormally low expression of FLOT1 may lead to the occurrence of neurological diseases, such as Alzheimer's disease, Parkinson's disease, major depressive disorder and other diseases. Additionally, it is also associated with dilated cardiomyopathy, pathogenic microbial infection, diabetes‑related diseases, and gynecological diseases, amongst other diseases. In the present review, the structure and localization of FLOT1, as well as the physiological processes it is involved in are reviewed, and then the upstream and downstream regulation of FLOT1 in human disease, particularly in different types of cancer and neurological diseases are discussed, with a focus on potentially targeting FLOT1 for the clinical treatment of several diseases.

FLOT1 promotes gastric cancer progression and metastasis through BCAR1/ERK signaling

Flotillin-1 (FLOT1) is a member of the flotillin family and serves as a hallmark of lipid rafts involved in the process of signaling transduction and vesicular trafficking. Here, we find FLOT1 promotes gastric cancer cell progression and metastasis by interacting with BCAR1, through ERK signaling. FLOT1 regulates BCAR1 phosphorylation and translocation. Overexpression of FLOT1 increases, while knockdown of FLOT1 decreases gastric cancer cell proliferation, migration and invasion. BCAR1 knockdown could block FLOT1 induced gastric cancer cell proliferation, migration and invasion. Re-expression of wildtype rather than mutant BCAR1 (Y410F) could partially restore FLOT1 knockdown induced gastric cancer cell migration and invasion, while the restore could be inhibited by ERK inhibitor. Furthermore, FLOT1 and BCAR1 expression is closely related to gastric cancer patients' poor outcome. Thus, our findings confirm that BCAR1 mediates FLOT1 induced gastric cancer progression and metastasis through ERK signaling, which may provide a novel pathway for gastric cancer treatment.

Exosomal miRNAs as novel avenues for breast cancer treatment

Breast cancer is the most commonly diagnosed cancer and a leading cause of death in women worldwide. It is a heterogeneous disease, as shown by the gene expression profiles of breast cancer samples. It begins in milk-producing ducts, with a high degree of diversity between and within tumors, as well as among cancer-bearing individuals. The enhanced prevalence of breast cancer is influenced by various hormonal, lifestyle, and environmental factors, and very early onset of the disease correlates strongly with the risk of local and distant recurrence. Many subtypes are difficult to treat with conventional therapeutic modalities, and therefore, optimal management and early diagnosis are the first steps to minimizing the mortality linked with breast cancer. The use of newer methods of nanotechnology extends beyond the concept of synthesizing drug delivery mechanisms into the creation of new therapeutics, such as delivering chemotherapeutics with nanomaterial properties. Exosomes, a class of nanovesicles, are emerging as novel tools for deciphering the patient-specific proteins and biomarkers across different disease models, including breast cancer. In this review, we address the role of exosomal miRNA in breast cancer diagnosis and treatment.

Flotillin-1 palmitoylation turnover by APT-1 and ZDHHC-19 promotes cervical cancer progression by suppressing IGF-1 receptor desensitization and proteostasis

We have shown that insulin-like growth factor-1 (IGF-1) induces palmitoylation turnover of Flotillin-1 (Flot-1) in the plasma membrane (PM) for cell proliferation, after IGF-1 receptor (IGF-1R) signaling activation. However, the enzymes responsible for the turnover have not been identified. Herein, we show that acyl protein thioesterases-1 (APT-1) catalyzes Flot-1 depalmitoylation, and zinc finger DHHC domain-containing protein palmitoyltransferase-19 (ZDHHC-19) repalmitoylation of the depalmitoylated Flot-1 for the turnover in cervical cancer cells. The turnover prevented desensitization of IGF-1R via endocytosis and lysosomal degradation, thereby exerting excessive IGF-1R activation in cervical cancer cells. FLOT1, LYPLA1 and ZDHHC19 were highly expressed, and epithelial-to-mesenchymal transition (EMT)-inducing TIAM1 and GREM1 coordinately upregulated in malignant cervical cancer tissues. And blocking the turnover suppressed the EMT, migration, and invasion of cervical cancer cells. Our study identifies the specific enzymes regulating Flot-1 palmitoylation turnover, and reveals a novel regulatory mechanism of IGF-1-mediated cervical cancer progression.

Astrocytes-Derived Small Extracellular Vesicles Hinder Glioma Growth

All cells are capable of secreting extracellular vesicles (EVs), which are not a means to eliminate unneeded cellular compounds but represent a process to exchange material (nucleic acids, lipids and proteins) between different cells. This also happens in the brain, where EVs permit the crosstalk between neuronal and non-neuronal cells, functional to homeostatic processes or cellular responses to pathological stimuli. In brain tumors, EVs are responsible for the bidirectional crosstalk between glioblastoma cells and healthy cells, and among them, astrocytes, that assume a pro-tumoral or antitumoral role depending on the stage of the tumor progression. In this work, we show that astrocyte-derived small EVs (sEVs) exert a defensive mechanism against tumor cell growth and invasion. The effect is mediated by astrocyte-derived EVs (ADEVs) through the transfer to tumor cells of factors that hinder glioma growth. We identified one of these factors, enriched in ADEVs, that is miR124. It reduced both the expression and function of the volume-regulated anion channel (VRAC), that, in turn, decreased the cell migration and invasion of murine glioma GL261 cells.

Dynamin-Independent Mechanisms of Endocytosis and Receptor Trafficking

Endocytosis is a fundamental mechanism by which cells perform housekeeping functions. It occurs via a variety of mechanisms and involves many regulatory proteins. The GTPase dynamin acts as a “molecular scissor” to form endocytic vesicles and is a critical regulator among the proteins involved in endocytosis. Some GTPases (e.g., Cdc42, arf6, RhoA), membrane proteins (e.g., flotillins, tetraspanins), and secondary messengers (e.g., calcium) mediate dynamin-independent endocytosis. These pathways may be convergent, as multiple pathways exist in a single cell. However, what determines the specific path of endocytosis is complex and challenging to comprehend. This review summarizes the mechanisms of dynamin-independent endocytosis, the involvement of microRNAs, and factors that contribute to the cellular decision about the specific route of endocytosis.

Flotillin-1 promotes progression and dampens chemosensitivity to cisplatin in gastric cancer via ERK and AKT signaling pathways

BACKGROUND

Several past studies have reported the overexpression of Flotillin-1 in a variety of cancer types. Cisplatin is a chemotherapeutic drug commonly used for cancer treatment. The present study investigated the role of Flotillin-1 in the progression of GC and assessed whether it assists in the chemical sensitization of GC cells toward cisplatin.

METHOD

The expression of Flotillin-1 was detected both in human gastric mucosal cells and GC cells. Next, siRNA and shRNA were used to construct a stable cell line expressing low levels of Flotillin-1. Furthermore, the Cell Counting Kit 8 (CCK-8), flow cytometry, and transwell assays were employed to detect the impact of Flotillin-1 on GC cells. In addition, a nude mouse model of human GC was used to verify the knockdown of Flotillin-1 to increase the sensitivity of GC cells to cisplatin.

RESULTS

Flotillin-1 was overexpressed in GC cells when compared to that in human gastric mucosal cells. The results for in vitro and vivo assays revealed that the knockdown of Flotillin-1 could significantly inhibit the proliferation of GC cells and increased the sensitivity of GC cells to cisplatin via the regulation of the protein kinase B (AKT) and extracellular signal-regulated kinase (ERK) signaling pathway.

CONCLUSION

Flotillin-1 might be used as a molecular marker for GC diagnosis and could be explored as a potential new target for the treatment of GC.

Bioengineered miR-124-3p prodrug selectively alters the proteome of human carcinoma cells to control multiple cellular components and lung metastasis in vivo

With the understanding of microRNA (miRNA or miR) functions in tumor initiation, progression, and metastasis, efforts are underway to develop new miRNA-based therapies. Very recently, we demonstrated effectiveness of a novel humanized bioengineered miR-124-3p prodrug in controlling spontaneous lung metastasis in mouse models. This study was to investigate the molecular and cellular mechanisms by which miR-124-3p controls tumor metastasis. Proteomics study identified a set of proteins selectively and significantly downregulated by bioengineered miR-124-3p in A549 cells, which were assembled into multiple cellular components critical for metastatic potential. Among them, plectin (PLEC) was verified as a new direct target for miR-124-3p that links cytoskeleton components and junctions. In miR-124-3p-treated lung cancer and osteosarcoma cells, protein levels of vimentin, talin 1 (TLN1), integrin beta-1 (ITGB1), IQ motif containing GTPase activating protein 1 (IQGAP1), cadherin 2 or N-cadherin (CDH2), and junctional adhesion molecule A (F11R or JAMA or JAM1) decreased, causing remodeling of cytoskeletons and disruption of cell-cell junctions. Furthermore, miR-124-3p sharply suppressed the formation of focal adhesion plaques, leading to reduced cell adhesion capacity. Additionally, efficacy and safety of biologic miR-124-3p therapy was established in an aggressive experimental metastasis mouse model in vivo. These results connect miR-124-3p-PLEC signaling to other elements in the control of cytoskeleton, cell junctions, and adhesion essential for cancer cell invasion and extravasation towards metastasis, and support the promise of miR-124 therapy.

MicroRNA-124 Alleviates Retinal Vasoregression via Regulating Microglial Polarization

Microglial activation is implicated in retinal vasoregression of the neurodegenerative ciliopathy-associated disease rat model (i.e., the polycystic kidney disease (PKD) model). microRNA can regulate microglial activation and vascular function, but the effect of microRNA-124 (miR-124) on retinal vasoregression remains unclear. Transgenic PKD and wild-type Sprague Dawley (SD) rats received miR-124 at 8 and 10 weeks of age intravitreally. Retinal glia activation was assessed by immunofluorescent staining and in situ hybridization. Vasoregression and neuroretinal function were evaluated by quantitative retinal morphometry and electroretinography (ERG), respectively. Microglial polarization was determined by immunocytochemistry and qRT-PCR. Microglial motility was examined via transwell migration assays, wound healing assays, and single-cell tracking. Our data showed that miR-124 inhibited glial activation and improved vasoregession, as evidenced by the reduced pericyte loss and decreased acellular capillary formation. In addition, miR-124 improved neuroretinal function. miR-124 shifted microglial polarization in the PKD retina from the pro-inflammatory M1 phenotype to the anti-inflammatory M2 phenotype by suppressing TNF-α, IL-1β, CCL2, CCL3, MHC-II, and IFN-γ and upregulating Arg1 and IL-10. miR-124 also decreased microglial motility in the migration assays. The transcriptional factor of C/EBP-α-PU.1 signaling, suppressed by miR-124 both in vivo (PKD retina) and in vitro (microglial cells), could serve as a key regulator in microglial activation and polarization. Our data illustrate that miR-124 regulates microglial activation and polarization. miR-124 inhibits pericyte loss and thereby alleviates vasoregression and ameliorates neurovascular function.

MicroRNAs: emerging driver of cancer perineural invasion

The perineural invasion (PNI), which refers to tumor cells encroaching on nerve, is a clinical feature frequently occurred in various malignant tumors, and responsible for postoperative recurrence, metastasis and decreased survival. The pathogenesis of PNI switches from 'low-resistance channel' hypothesis to 'mutual attraction' theory between peripheral nerves and tumor cells in perineural niche. Among various molecules in perineural niche, microRNA (miRNA) as an emerging modulator of PNI through generating RNA-induced silencing complex (RISC) to orchestrate oncogene and anti-oncogene has aroused a wide attention. This article systematically reviewed the role of microRNA in PNI, promising to identify new biomarkers and offer cancer therapeutic targets.

Long non-coding RNA A1BG-AS1 promotes tumorigenesis in breast cancer by sponging microRNA-485-5p and consequently increasing expression of FLOT1 expression

The dysregulated long non-coding RNA A1BG antisense RNA 1 (A1BG-AS1) has been implicated in the oncogenicity of hepatocellular carcinoma. Using reverse transcription quantitative polymerase chain reaction in this study, we detected A1BG-AS1 expression in breast cancer and elucidated the regulatory functions and exact mechanisms of A1BG-AS1 in breast cancer cells. The regulatory functions of A1BG-AS1 were examined in vitro using the Cell Counting Kit-8 assay, flow cytometric, and Transwell migration and invasion assays and in vivo through tumor xenograft experiments. In addition, we performed bioinformatics analysis, luciferase reporter assay, RNA immunoprecipitation, and rescue experiments to verify the interaction among A1BG-AS1, microRNA-485-5p (miR-485-5p), and flotillin-1 (FLOT1) in breast cancer. We found A1BG-AS1 to be highly expressed in breast cancer tissues and cell lines. In terms of function, depleted A1BG-AS1 markedly suppressed cell proliferation, accelerated cell apoptosis, and hindered cell migration and invasion in breast cancer. Furthermore, A1BG-AS1 interference reduced tumor growth in vivo. Mechanistic investigations confirmed that A1BG-AS1 directly interacted with miR-485-5p as a molecular sponge. We demonstrated that FLOT1 is a direct target of miR-485-5p, which could be positively regulated by A1BG-AS1 by competing for miR-485-5p. Rescue experiments clearly showed that the downregulation of miR-485-5p and upregulation of FLOT1 were capable of reversing the anticancer activities of A1BG-AS1 deficiency in terms of breast cancer cell malignancy. A1BG-AS1 acts as a miR-485-5p sponge and subsequently increases FLOT1 expression in breast cancer cells, ultimately facilitating cancer progression. Hence, the A1BG-AS1/miR-485-5p/FLOT1 pathway might offer a novel therapeutic perspective for breast cancer.

Tumor Suppressive Effects of miR-124 and Its Function in Neuronal Development

MicroRNA-124 (miR-124) is strongly expressed in neurons, and its expression increases as neurons mature. Through DNA methylation in the miR-124 promoter region and adsorption of miR-124 by non-coding RNAs, miR-124 expression is known to be reduced in many cancer cells, especially with high malignancy. Recently, numerous studies have focused on miR-124 due to its promising tumor-suppressive effects; however, the overview of their results is unclear. We surveyed the tumor-suppressive effect of miR-124 in glial cell lineage cancers, which are the most frequently reported cancer types involving miR-124, and in lung, colon, liver, stomach, and breast cancers, which are the top five causes of cancer death. Reportedly, miR-124 not only inhibits proliferation and accelerates apoptosis, but also comprehensively suppresses tumor malignant transformation. Moreover, we found that miR-124 exerts its anti-tumor effects by regulating a wide range of target genes, most notably STAT3 and EZH2. In addition, when compared to the original role of miR-124 in neuronal development, we found that the miR-124 target genes that contribute to neuronal maturation share similarities with genes that cause cancer cell metastasis and epithelial-mesenchymal transition. We believe that the two apparently unrelated fields, cancer and neuronal development, can bring new discoveries to each other through the study of miR-124.

LncRNA-cCSC1 promotes cell proliferation of colorectal cancer through sponging miR-124-3p and upregulating CD44

LncRNA-cCSC1 is highly expressed in colorectal cancer (CRC). The study was designed to evaluate the function and mechanism of lncRNA-cCSC1 in cell proliferation of CRC. RT-PCR was used to measure the expression levels of lncRNA-cCSC1 in CRC cell lines. CCK-8, colony formation, EdU staining, flow cytometry and Western blot were performed to examine the effect of interference with lncRNA-cCSC1 expression on cell proliferation. miR-124-3p and the target genes of miR-124-3p were investigated using bioinformatics analysis and verified by dual-luciferase reporter, RT-PCR and Western blot. Rescue experiments were carried out to confirm the role of miR-124-3p in cell proliferation of CRC. Our results showed that cell proliferation of CRC was promoted by lncRNA-cCSC1 upregulation and inhibited by lncRNA-cCSC1 downregulation. In addition, miR-124-3p is predicted to be the target of lncRNA-cCSC1 and is negatively correlated with lncRNA-cCSC1. Moreover, the addition of miR-124-3p mimics or inhibitor reversed the effects induced by lncRNA-cCSC1 overexpression or silencing on cell proliferation of CRC. Additionally, lncRNA-cCSC1 regulated the expression level of CD44, a target gene of miR-124-3p. Finally, we studied the effects of the lncRNA-cCSC1/miR-124-3p axis on CD44. These results indicate that lncRNA-cCSC1 promotes cell proliferation of CRC through sponging miR-124-3p and upregulating CD44.

Exosomal microRNAs: Pleiotropic Impacts on Breast Cancer Metastasis and Their Clinical Perspectives

As a major threat factor for female health, breast cancer (BC) has garnered a lot of attention for its malignancy and diverse molecules participating in its carcinogenesis process. Among these complex carcinogenesis processes, cell proliferation, epithelial-to-mesenchymal transition (EMT), mesenchymal-to-epithelial transition (MET), and angiogenesis are the major causes for the occurrence of metastasis and chemoresistance which account for cancer malignancy. MicroRNAs packaged and secreted in exosomes are termed "exosomal microRNAs (miRNAs)". Nowadays, more researches have uncovered the roles of exosomal miRNAs played in BC metastasis. In this review, we recapitulated the dual actions of exosomal miRNAs exerted in the aggressiveness of BC by influencing migration, invasion, and distant metastasis. Next, we presented how exosomal miRNAs modify angiogenesis and stemness maintenance. Clinically, several exosomal miRNAs can govern the transformation between drug sensitivity and chemoresistance. Since the balance of the number and type of exosomal miRNAs is disturbed in pathological conditions, they are able to serve as instructive biomarkers for BC diagnosis and prognosis. More efforts are needed to connect the theoretical studies and clinical traits together. This review provides an outline of the pleiotropic impacts of exosomal miRNAs on BC metastasis and their clinical implications, paving the way for future personalized drugs.

MicroRNA124 and microRNA21-5p regulate migration, proliferation and differentiation of rat bone marrow mesenchymal stem cells

Mesenchymal stem cells (MSCs) are multipotent stromal cells that can be a useful source of cells for the treatment of many diseases, including neurologic diseases. The curative effect of MSCs relies mostly on cell’s capacity of migration, proliferation and differentiation. MicroRNAs (miRNAs) are small non-coding RNAs that play important roles on regulating various cell behaviors. Here, we report that miRNA-124 (miR124) and miRNA-21-5p (miR21-5p) display different regulatory roles on migration, proliferation and neuron differentiation of MSCs. MiR124 was shown greatly promoting MSCs migration and neuronal differentiation. MiR21-5p could significantly enhance the proliferation and neuronal differentiation ability of MSCs. MiR124 and miR21-5p synergistically promote differentiation of MSCs into neurons. Collectively, miR124 and miR21-5p can functionally regulate cell migration, proliferation and neuronal differentiation of MSCs. Therefore, miR124 and miR21-5p may be promising tools to improve transplantation efficiency for neural injury.

Evaluation of MicroRNA-124 Expression in Renal Cell Carcinoma

The Wingless/INT (WNT) signaling network has roles in renal cancer development. It was shown that the tumor-suppressor microRNA-124 (miR-124) is associated with the Wnt pathway. Thus, we aimed to measure miR-124 expression levels to evaluate whether it is a prognostic marker or a potential treatment strategy. Thirty tumor and 30 surrounding healthy kidney tissues from the same subjects diagnosed with renal cell carcinoma (RCC), were included in the study. The expression levels of miR-124 were measured with real-time polymerase chain reaction (qPCR) and determined by the 2^–ΔΔCT method. The Statistical Package for Social Science (SPSS) version 22 program was used for statistical analyses and a p value of 0.05 was considered to be statistically significant. The expression levels of miR-124 was found to be about 3-fold lower in tumors than in healthy tissues (p 0.001) and decreased expression levels correlated with tumor stage, tumor diameter, body mass index (BMI) and neutrophil values (p 0.05). Our results showed that miR-124 expression levels are associated with RCC. MicroRNA-124 may be assessed as a biomarker in prognosis and the restoration of miR-124 expression might be effective in the treatment of RCC.

MicroRNA-155 is upregulated in the placentas of patients with preeclampsia and affects trophoblast apoptosis by targeting SHH/GLi1/BCL2

The pathogenesis of preeclampsia (PE) is complicated and multiple risk factors have been associated with its occurrence. Still, the underlying molecular mechanisms involved in PE remain elusive. Aberrant apoptosis and insufficient invasion of trophoblasts have been observed and are considered vital pathological features in PE. Herein, we found that miR-155 can specifically degrade the mRNA of the Hedgehog ligand sonic hedgehog (SHH), using dual luciferase reporter assays. Quantitative real-time PCR found that administering miR-155 mimics or inhibitors could significantly decrease or increase the expression of SHH in the trophoblasts, respectively. The transcription levels of miR-155 in the placenta were higher in patients with PE compared to the levels in healthy pregnant women, as shown by quantitative real-time PCR. Serum levels of miR-155 could predict the diagnosis of PE by receiver operating characteristic curve analysis and diagnosis evaluation tests. A significant increase in apoptosis was observed after administering miR-155 in HTR8/SVneo cells cultured ex vivo, accompanied by reduced proliferation. Mechanistically, transcriptional activity and expression of GLi1 were also inhibited under treatment of miR-155, and could be recovered after supplying additional recombinant human SHH to primary trophoblasts from patients, as determined by luciferase activity assays and western blotting. We further found that inhibiting miR-155 increased the production of SHH and improved the phenotype in primary trophoblasts from patients with PE. Our data show that miR-155 regulates apoptosis of trophoblasts in PE, which has potential value for predicting PE risk and might be deemed as a therapeutic target for treating PE.

A paclitaxel and microRNA-124 coloaded stepped cleavable nanosystem against triple negative breast cancer

Background

Triple negative breast cancer (TNBC) is one of the most biologically aggressive breast cancers and lacks effective treatment options, resulting in a poor prognosis. Therefore, studies aiming to explore new therapeutic strategies for advanced TNBC are urgently needed. According to recent studies, microRNA-124 (miR124) not only inhibits tumour growth but also increases the sensitivity of TNBC to paclitaxel (PTX), suggesting that a platform combining PTX and miR124 may be an advanced solution for TNBC.

Results

Herein, we constructed a stepped cleavable calcium phosphate composite lipid nanosystem (CaP/LNS) to codeliver PTX and miR124 (PTX/miR124-NP). PTX/miR124-NP exhibited superior tumor microenvironment responsive ability, in which the surface PEG layer was shed in the mildly acidic environment of tumor tissues and exposed oligomeric hyaluronic acid (o-HA) facilitated the cellular uptake of CaP/LNS by targeting the CD44 receptor on the surface of tumor cells. Inside tumour cells, o-HA detached from CaP/LNS due to the reduction of disulfide bonds by glutathione (GSH) and inhibited tumour metastasis. Then, PTX and miR124 were sequentially released from CaP/LNS and exerted synergistic antitumour effects by reversing the Epithelial-Mesenchymal Transition (EMT) process in MDA-MB-231 cells. Moreover, PTX/miR124-NP showed significant antitumour efficiency and excellent safety in mice bearing MDA-MB-231 tumours.

Conclusion

Based on these results, the codelivery of PTX and miR124 by the CaP/LNS nanosystem might be a promising therapeutic strategy for TNBC.

MicroRNA-124 suppresses the invasion and proliferation of breast cancer cells by targeting TFAP4

MicroRNA (miRNA/miR)-124 is widely accepted as the suppressor of different tumors. The present study aimed to improve understanding of the potential role of miR-124 in breast cancer. The gene expression profile change derived from the overexpression of miR-124 was investigated using RNA sequencing and bioinformatics analysis of the breast cancer cell line SKBR3. The results demonstrated that the gene expression profile of SKBR3 cells significantly changed. In addition, the transcription factor activating enhancer-binding protein 4 (TFAP4) gene was identified among the top 10 differentially expressed genes, and was identified as a novel target gene of miR-124 using a dual-luciferase reporter assay. TFAP4 knockdown in notably impaired SKBR3 cell migration and proliferation, which was consistent with decreasing migration and proliferation ability following overexpression of miR-124. Taken together, these results suggest that overexpression of miR-124 can suppress the migration and proliferation of SKBR3 cells by tarsgeting TFAP4. Thus, TFAP4 may act as a novel therapeutic target of breast cancer.

Flotillin membrane domains in cancer

Flotillins 1 and 2 are two ubiquitous, highly conserved homologous proteins that assemble to form heterotetramers at the cytoplasmic face of the plasma membrane in cholesterol- and sphingolipid-enriched domains. Flotillin heterotetramers can assemble into large oligomers to form molecular scaffolds that regulate the clustering of at the plasma membrane and activity of several receptors. Moreover, flotillins are upregulated in many invasive carcinomas and also in sarcoma, and this is associated with poor prognosis and metastasis formation. When upregulated, flotillins promote plasma membrane invagination and induce an endocytic pathway that allows the targeting of cargo proteins in the late endosomal compartment in which flotillins accumulate. These late endosomes are not degradative, and participate in the recycling and secretion of protein cargos. The cargos of this Upregulated Flotillin–Induced Trafficking (UFIT) pathway include molecules involved in signaling, adhesion, and extracellular matrix remodeling, thus favoring the acquisition of an invasive cellular behavior leading to metastasis formation. Thus, flotillin presence from the plasma membrane to the late endosomal compartment influences the activity, and even modifies the trafficking and fate of key protein cargos, favoring the development of diseases, for instance tumors. This review summarizes the current knowledge on flotillins and their role in cancer development focusing on their function in cellular membrane remodeling and vesicular trafficking regulation.

Interplay between p53 and non-coding RNAs in the regulation of EMT in breast cancer

The epithelial-mesenchymal transition (EMT) plays a pivotal role in the differentiation of vertebrates and is critically important in tumorigenesis. Using this evolutionarily conserved mechanism, cancer cells become drug-resistant and acquire the ability to escape the cytotoxic effect of anti-cancer drugs. In addition, these cells gain invasive features and increased mobility thereby promoting metastases. In this respect, the process of EMT is critical for dissemination of solid tumors including breast cancer. It has been shown that miRNAs are instrumental for the regulation of EMT, where they play both positive and negative roles often as a part of a feed-back loop. Recent studies have highlighted a novel association of p53 and EMT where the mutation status of p53 is critically important for the outcome of this process. Interestingly, p53 has been shown to mediate its effects via the miRNA-dependent mechanism that targets master-regulators of EMT, such as Zeb1/2, Snail, Slug, and Twist1. This regulation often involves interactions of miRNAs with lncRNAs. In this review, we present a detailed overview of miRNA/lncRNA-dependent mechanisms that control interplay between p53 and master-regulators of EMT and their importance for breast cancer.

NCBP3/SNHG6 inhibits GBX2 transcription in a histone modification manner to facilitate the malignant biological behaviour of glioma cells

RNA-binding proteins (RBPs) are significantly dysregulated in glioma. In this study, we demonstrated the upregulation of Nuclear cap-binding subunit 3 (NCBP3) in glioma tissues and cells. Further, knockdown of NCBP3 inhibited the malignant progression of glioma. NCBP3 directly bound to small nucleolar RNA host gene 6 (SNHG6) and stabilized SNHG6 expression. In contrast, the gastrulation brain homeobox 2 (GBX2) transcription factor was downregulated in glioma tissues and cells. SNHG6 inhibited GBX2 transcription by mediating the H3K27me3 modification induced by polycomb repressive complex 2 (PRC2). Moreover, GBX2 decreased the promoter activities and downregulated the expression of the flotillin protein family 1 (FLOT1) oncogene. In conclusion, NCBP3/SNHG6 inhibits GBX2 transcription in a PRC2-dependent manner to facilitate the malignant progression of gliomas.

microRNA-124 inhibits stem-like properties and enhances radiosensitivity in nasopharyngeal carcinoma cells via direct repression of expression of JAMA

Cancer stem cells (CSCs) are a source of tumour recurrence in patients with nasopharyngeal carcinoma (NPC); however, the function of microRNA‐124 (miR‐124) in NPC CSCs has not been clearly defined. In this study, we investigated the role of miR‐124 in NPC CSCs. qRT‐PCR was performed to measure miR‐124 expression in NPC tissues and cell lines and the effects of miR‐124 on stem‐like properties and radiosensitivity of NPC cells measured. Luciferase reporter assays and rescue experiments were used to investigate the interaction of miR‐124 with the 3′UTR of junctional adhesion molecule A (JAMA). Finally, we examined the effects of miR‐124 in an animal model and clinical samples. Down‐regulation of miR‐124 was detected in cancer tissues and was inversely associated with tumour stage and lymph node metastasis. Overexpression of miR‐124 inhibited stemness properties and enhanced radiosensitivity of NPC cells in vitro and in vivo via targeting JAMA. Up‐regulation of miR‐124 was correlated with superior overall survival of patients with NPC. Our study demonstrates that miR‐124 can inhibit stem‐like properties and enhance radiosensitivity by directly targeting JAMA in NPC. These findings provide novel insights into the molecular mechanisms underlying therapy failure in NPC.

Potential miRNAs for miRNA-Based Therapeutics in Breast Cancer

MicroRNAs (miRNAs) are small non-coding RNAs that can post-transcriptionally regulate the genes involved in critical cellular processes. The aberrant expressions of oncogenic or tumor suppressor miRNAs have been associated with cancer progression and malignancies. This resulted in the dysregulation of signaling pathways involved in cell proliferation, apoptosis and survival, metastasis, cancer recurrence and chemoresistance. In this review, we will first (i) provide an overview of the miRNA biogenesis pathways, and in vitro and in vivo models for research, (ii) summarize the most recent findings on the roles of microRNAs (miRNAs) that could potentially be used for miRNA-based therapy in the treatment of breast cancer and (iii) discuss the various therapeutic applications.

Reduced levels of miR-485-5p in HPV-infected cervical cancer promote cell proliferation and enhance invasion ability

Cervical cancer (CC) is the most common gynecological malignancy, with high incidence and mortality rates in China. The microRNA miR‐485‐5p has previously been reported to serve as a negative regulator of tumorigenesis in breast cancer and hepatocellular carcinoma, and miR‐485‐5p has been observed to be differentially expressed between CC and normal control tissue. Here, we confirmed that miR‐485‐5p expression is lower in CC than in adjacent normal tissue and proceeded to investigate the effects of miR‐485 on tumor behavior in CC cell lines. We report that miR‐485‐5p transcription is decreased in HPV‐infected CC tissue, and levels of miR‐485 in clinical samples are positively correlated with the 5‐year overall survival rate. The Transwell assay showed that miR‐485‐5p inhibited cell invasion and migration but had no influence on apoptosis and cell proliferation. Using a luciferase reporter assay, we demonstrated that miR‐485‐5p partially abrogated cell migration and proliferation by targeting FLOT‐1 mRNA. Transfection of HPV‐infected cervical carcinoma cells with an adenovirus vector encoding human FLOT‐1 partially diminished the inhibitory effects of miR‐485 on cell invasion. Taken, together, these data demonstrated that miR‐485‐5p suppresses the invasion of cancer cells by targeting FLOT‐1 in HPV‐infected cervical carcinoma cells.

MiR-138 Suppresses the PDK1 Expression to Decrease the Oxaliplatin Resistance of Colorectal Cancer

Background

Oxaliplatin is one kind of platinum-based drug. It is effective and commonly used in the treatment of colorectal cancer (CRC). However, development of acquired drug resistance is still a big obstacle during the oxaliplatin therapy. It is urgent to take strategies to decrease the oxaliplatin resistance of CRC.

Materials and Methods

Oxaliplatin-resistant HT29 and SW480 (HT29/R and SW480/R) cells were acquired through long-term exposure to oxaliplatin by using the routine HT29 and SW480 cells. Relative glucose consumption, lactate generation and LDH activity were tested to evaluate the glycolysis of CRC cell lines. MTT assays were conducted to evaluate the differences of oxaliplatin sensitivity between HT29/R (SW480/R) cells and their parental HT29 (SW480) cells. Regulation of miR-138 on PDK1 was confirmed through qRT-PCR, Western blot and dual-luciferase reporter assays. Reactive oxygen species (ROS) levels were measured by flow cytometry.

Results

HT29/R and SW480/R cells exhibited higher glucose consumption, lactate production and LDH activity compared to their parental HT29 and SW480 cells. However, oxygen consumption rate (OCR) in HT29/R and SW480/R cells is lower than that in HT29 and SW480 cells, respectively. Results of MTT assays showed that treatment with miR-138 can increase the cytotoxicity of oxaliplatin to HT29/R and SW480/R cells. Research on mechanisms showed that PDK1 was the target of miR-138. Overexpression of miR-138 can inhibit the expression of PDK1, and thus increase the OCR of HT29/R and SW480/R cells. Under the treatment of oxaliplatin, the miR-138-overexpressed HT29/R and SW480/R cells generated more amount of ROS to get into the apoptosis process.

Conclusion

Overexpression of miR-138 suppressed the PDK1 expression to decrease the oxaliplatin resistance of CRC.

Cationic Polymer Nanoparticles-Mediated Delivery of miR-124 Impairs Tumorigenicity of Prostate Cancer Cells

MicroRNAs (miRNAs) play a pivotal role in regulating the expression of genes involved in tumor development, invasion, and metastasis. In particular, microRNA-124 (miR-124) modulates the expression of carnitine palmitoyltransferase 1A (CPT1A) at the post-transcriptional level, impairing the ability of androgen-independent prostate cancer (PC3) cells to completely metabolize lipid substrates. However, the clinical translation of miRNAs requires the development of effective and safe delivery systems able to protect nucleic acids from degradation. Herein, biodegradable polyethyleneimine-functionalized polyhydroxybutyrate nanoparticles (PHB-PEI NPs) were prepared by aminolysis and used as cationic non-viral vectors to complex and deliver miR-124 in PC3 cells. Notably, the PHB-PEI NPs/miRNA complex effectively protected miR-124 from RNAse degradation, resulting in a 30% increase in delivery efficiency in PC3 cells compared to a commercial transfection agent (Lipofectamine RNAiMAX). Furthermore, the NPs-delivered miR-124 successfully impaired hallmarks of tumorigenicity, such as cell proliferation, motility, and colony formation, through CPT1A modulation. These results demonstrate that the use of PHB-PEI NPs represents a suitable and convenient strategy to develop novel nanomaterials with excellent biocompatibility and high transfection efficiency for cancer therapy.

MicroRNA-124: An emerging therapeutic target in cancer

MicroRNAs (miRNAs) are noncoding single‐stranded RNAs, approximately 20‐24 nucleotides in length, known as powerful posttranscriptional regulators. miRNAs play important regulatory roles in cellular processes by changing messenger RNA expression and are widely involved in human diseases, including tumors. It has been reported in the literature that miRNAs have a precise role in cell proliferation, programmed cell death, differentiation, and expression of coding genes. MicroRNA‐124 (miR‐124) has reduced exparession in various human neoplasms and is believed to be related to the occurrence, development, and prognosis of malignant tumors. In our review, we focus on the specific molecular functions of miR‐124 and the downstream gene targets in major cancers, which provide preclinical evidence for the treatment of human cancer. Although some obstacles exist, miR‐124 is still attracting intensive research focus as a promising and effective anticancer weapon.

MiR-124 reversed the doxorubicin resistance of breast cancer stem cells through STAT3/HIF-1 signaling pathways

Various drug treatments including doxorubicin (DOX) have been proved efficient in the suppression of breast cancer. Nonetheless, drug resistance became an obstacle in the therapeutic process. According to recent literatures, breast cancer stem cells (BCSCs) were considered contributing to drug resistance, besides, microRNAs (miRNAs) could regulate proteins associated with drug resistance in human breast cancer. To further understand the inner mechanism of drug resistance in breast cancer and look for remedy methods, we referred to bioinformatic analysis and predicted that signal transducer and activator of transcription 3 (STAT3) and miR-124 was overexpressed in MCF7-R cells (MCF7 cells resistant to DOX) compared with MCF cells. Expression levels of RNA and protein were separately determined by qRT-PCR and western blot. Dual luciferase assay was performed to verify the targeting relationship between STAT3 and miR-124. Optical density (OD) values and apoptotic rates of cells were respectively determined via MTT assays and flow cytometric analysis. Cell invasion was detected to verify drug resistance. Results of above assays indicated that STAT3 was highly expressed in MCF7-R cells than in MCF7 cell lines and affected doxorubicin resistance of BCSCs, and miR-124 reversed the doxorubicin resistance of breast cancer stem cells through targeting STAT3 to control the HIF-1 signaling pathway. To conclude, this research may be valuable for the treatment of breast cancer as the restoration of miR-124 and inhibition of STAT3 could be applied to therapeutic strategy and help overcome drug resistance.

Clinical significance and comparison of flotillin 1 expression in left and right colon cancer

Flotillin 1 (FLOT1) is increasingly implicated in various types of cancer, and has been reported to influence tumorigenesis and cancer progression, leading to poor prognosis for survival time; however, its expression in colorectal cancer (CRC) and its influence on various clinicopathological parameters of this disease remain unknown. In the present study, FLOT1 expression and its effect on different clinicopathological parameters were assessed immunohistochemically and histologically in 81 CRC and 81 non-tumorous colon tissue samples. The immunohistochemical staining was scored semi-quantitatively. The association of FLOT1 expression with various parameters and its effect on overall survival time was also assessed. FLOT1 was upregulated in the CRC tissue, with increased expression in the right colon tissue samples compared with those of left colon. Increased FLOT1 expression in CRC tissue samples was associated with tumor volume, differentiation, tumor grade and poor overall survival time. In the right colon tissue samples in particular, there was a notable association with tumor volume and grade, indicating its effect on proliferation and tumor stage at this site. A multivariate Cox regression hazard analysis revealed that only tumor grade and differentiation were the independent predictors of overall survival time in patients with CRC. Together, the results of the present study suggest that FLOT1 serves important functions in the proliferation and progression of CRC, contributes to decreased survival time, and may serve as a novel therapeutic target for the treatment of CRC.

Circular RNAs in Cancer: emerging functions in hallmarks, stemness, resistance and roles as potential biomarkers

Circular RNAs (circRNAs) are a class of RNA molecules with closed loops and high stability. CircRNAs are abundantly expressed in eukaryotic organisms and exhibit both location- and step-specificity. In recent years, circRNAs are attracting considerable research attention attributed to their possible contributions to gene regulation through a variety of actions, including sponging microRNAs, interacting with RNA-binding proteins, regulating transcription and splicing, and protein translation. Growing evidence has revealed that circRNAs play critical roles in the development and progression of diseases, especially in cancers. Without doubt, expanding our understanding of circRNAs will enrich knowledge of cancer and provide new opportunities for cancer therapy. In this review, we provide an overview of the characteristics, functions and functional mechanisms of circRNAs. In particular, we summarize current knowledge regarding the functions of circRNAs in the hallmarks, stemness, resistance of cancer, as well as the possibility of circRNAs as biomarkers in cancer.

MicroRNA-6809-5p mediates luteolin-induced anticancer effects against hepatoma by targeting flotillin 1

BACKGROUND

Luteolin (3,4,5,7-tetrahydroxy flavone) is a natural flavonoid abundant in fruits and vegetables. Although luteolin has shown pro-apoptotic activity in hepatocellular carcinoma (HCC) cells, the underlying molecular mechanism has not yet been clarified.

PURPOSE

The aim of this study is to identify novel miRNAs involved in the action of luteolin in HCC cells and to explore the biological roles of these miRNAs.

METHODS

The effect of luteolin on HCC cell growth was assessed using CCK-8 colony formation assay, flow cytometric analysis in vitro, and a xenograft model in vivo. miRNA expression profiles were assessed using next-generation sequencing. Differentially expressed miRNAs were validated by quantitative PCR. Bioinformatics analysis and luciferase reporter assay were utilized to confirm the binding of miR-6809-5p to the 3'-untranslated region (3'-UTR) of flotillin 1 (FLOT1). Furthermore, the effects of ectopic FLOT1 and miR-6809-5 expression on cell proliferation, colony formation, and cell apoptosis were also assessed. Western blotting analysis was used to detect activation of multiple signaling molecules including Erk1/2, p38, JNK, and NF-κB/p65 in the MAPK pathway.

RESULTS

It was found that luteolin significantly inhibited HCC growth and caused apoptosis and cell cycle arrest at the G0/G1 phase in Huh7 cells, at the G2/M phase in HepG2 cells in vitro. Tumorigenic studies revealed that luteolin treatment significantly suppressed HCC growth in vivo. miR-6809-5p was upregulated by luteolin. Overexpression of miR-6809-5p suppressed HCC cell growth, while knockdown of miR-6809-5p reversed the anticancer effect of luteolin. With regards to its signaling mechanism, miR-6809-5p directly targets FLOT1in HCC cells. Enforced expression of FLOT1 prevented miR-6809-5p-mediated growth suppression. Downregulation of FLOT1 exerted growth-suppressive effects on HCC cells. Multiple signaling pathways including Erk1/2, p38, JNK, and NF-κB/p65 were inactivated by miR-6809-5p overexpression or FLOT1 downregulation.

CONCLUSION

These findings indicated that miR-6809-5p mediates the growth-suppressive activity of luteolin in HCC, which is causally linked to FLOT1 downregulation. Induction of miR-6809-5p may provide therapeutic benefits in the treatment of HCC.

FLOT1 promotes tumor development, induces epithelial-mesenchymal transition, and modulates the cell cycle by regulating the Erk/Akt signaling pathway in lung adenocarcinoma

Background

FLOT1 is a scaffolding protein of lipid rafts that is believed to be involved in numerous cellular processes. However, few studies have explored the function of FLOT1 in the development of lung adenocarcinoma (LUAD) and the underlying mechanisms of FLOT1 activity.

Methods

FLOT1 knockdown and overexpression models were constructed via lentivirus. Cell growth, invasion, migration, and apoptosis were detected to evaluate the role of FLOT1 in LUAD development. Epithelial–mesenchymal transition (EMT) and cell cycle regulatory markers were then examined. Finally, the influence of FLOT1 on the Erk/Akt signaling pathway was investigated.

Results

FLOT1 promoted cell growth, invasion, and migration and inhibited cell apoptosis. In addition, FLOT1 induced EMT and modulated the cell cycle by activating the Erk/Akt signaling pathway.

Conclusion

The findings indicate a significant role of FLOT1 in LUAD development. Targeting FLOT1 may be a potential therapeutic strategy for LUAD.

Comprehensive circRNA expression profile during ischemic postconditioning attenuating hepatic ischemia/reperfusion injury

Ischemic postconditioning (IPO) attenuates hepatic ischemia/reperfusion (I/R) injury. The aim of this study was to explore the role of circular RNAs (circRNAs) in the protective mechanism of IPO. In this study, microarray hybridization analysis was performed to determine the circRNA expression profile. Briefly, a total of 1599 dysregulated circRNAs were detected. The competitive endogenous RNA (ceRNA) network, including 6 circRNAs, 47 miRNAs and 90 mRNAs, indicated that the potential “housekeeping” function of circRNAs is dysregulated in hepatic I/R injury. Based on the validation results of selected circRNAs, miRNAs and mRNAs following qRT-PCR amplification, the mmu_circRNA_005186-miR-124-3p-Epha2 pathway was constructed. Dual-luciferase reporter analysis showed that miR-124-3p interacted directly with mmu_circRNA_005186 and Epha2 through the predicted binding sites, which suggested that mmu_circRNA_005186, serving as a miRNA sponge for miR-124-3p, regulated the expression of Epha2. Functionally, we explored the mechanism of mmu_circRNA_005186 in LPS-treated RAW264.7 cells which simulated the inflammation in hepatic I/R injury. We found that mmu_circRNA_005186 silencing attenuated the LPS-induced inflammation and was associated with miR-124-3p upregulation and Epha2 downregulation. Our study is the first to show that circRNAs are closely related to hepatic I/R injury and IPO and suggests that targeting mmu_circRNA_005186-miR-124-3p-Epha2 pathway might attenuate hepatic I/R injury.

Roles of flotillins in tumors

The identification and use of molecular biomarkers have greatly improved the diagnosis and treatment of malignant tumors. However, a much deeper understanding of oncogenic proteins is needed for the benefit to cancer patients. The lipid raft marker proteins, flotillin-1 and flotillin-2, were first found in goldfish retinal ganglion cells during axon regeneration. They have since been found in a variety of cells, mainly on the inner surface of cell membranes, and not only act as a skeleton to provide a platform for protein-protein interactions, but also are involved in signal transduction, nerve regeneration, endocytosis, and lymphocyte activation. Previous studies have shown that flotillins are closely associated with tumor development, invasion, and metastasis. In this article, we review the functions of flotillins in relevant cell processes, their underlying mechanisms of action in a variety of tumors, and their potential applications to tumor molecular diagnosis and targeted therapy.

The clinical significance of miR-335, miR-124, miR-218 and miR-484 downregulation in gastric cancer

Gastric cancer (GC) is one of the leading types of malignancy worldwide, particularly in Asian populations. Although the exact molecular mechanism of GC development remains unknown, microRNA (miRNA) has recently been shown to be involved. The current study aims to investigate the expression levels of bioinformatically ranked miRNAs in gastric tissues. Using bioinformatics tools, we prioritized miRNAs thought to be implicated in GC. Furthermore, polyA-qPCR was used to validate bioinformatics findings in 40 GC, 31 normal gastric tissue (NG) and 45 gastric dysplasia (GD) samples. As identified by bioinformatics analysis, miR-335 was shown to be the top-ranked miRNA implicated in GC. Moreover, a significant downregulation of miR-335, miR-124, miR-218 and miR-484 was found in GC and GD compared to NG samples. We found bioinformatics to be an efficient approach to finding candidate miRNAs relevant to GC development. Finally, the findings show that downregulation of miRNAs such as miR-124 and miR-218 in gastric tissue can be a significant indicator for neoplastic transformation.

Circular RNA HIPK3 promotes gallbladder cancer cell growth by sponging microRNA-124

Recent studies have implied that circHIPK3, an abundant circular RNA (circRNA), participates in tumorigenesis and cancer progression. Its expression and potential functions in human gallbladder cancer were examined in this study. We show that circHIPK3 is upregulated in human gallbladder cancer cells. But its level is low in gallbladder epithelial cells. circHIPK3 silencing by targeted siRNA potently inhibited survival and proliferation of established and primary human gallbladder cancer cells, while inducing cell apoptosis. Conversely, ectopic over-expression of circHIPK3 can further promote cancer cell proliferation. In gallbladder cancer cells, circHIPK3 sponged the tumor-suppressive microRNA-124 (miR-124) to sequester and inhibit its activity, thereby leading to increased expression of miR-124 targets, including ROCK1 (rho-associated protein kinase 1) and CDK6 (rho-associated protein kinase). Ectopic over-expression of miR-124 b y a lentiviral vector mimicked and abolished actions by circHIPK3 siRNA in gallbladder cancer cells. At last, we show that circHIPK3 is upregulated in human gallbladder cancer tissues, which is correlated with miR-124 downregulation and ROCK1-CDK6 upregulation. Together, we conclude that circHIPK3 promotes gallbladder cancer cell growth possibly by sponging miR-124. The over-expressed circHIPK3 could be a novel therapeutic target and diagnosis marker of human gallbladder cancer.

Flotilin-1 promotes the tumorigenicity and progression of malignant phenotype in human lung adenocarcinoma

Lung adenocarcinoma (LUAD) accounts for the most common histological subtype of lung cancer which remains the leading cause of cancer death worldwide. The discovery of more sensitive and specific novel target biomarkers for predicting the development and progression of LUAD is imperative. Flotillin-1 (Flot-1) has been reported to have important roles in the progression of several tumor types but not been reported in the progression of LUAD. Here, we demonstrated that the expression of flotillin-1 was upregulated in 5 LUAD cells. Moreover, multiple approaches were used to explore the tumorigenicity of flotillin-1 in LUAD cell lines. The expression levels of flotillin-1 were analyzed by immunoblotting after overexpression and siRNA-based knockdown. Cell proliferation, scratch wound healing, transwell migration and matrigel invasion and xenograft tumor growth assays were used to determine the role of flotillin-1 in LUAD progression. Downregulation of flotillin-1 reversed, whereas upregulation of flotillin-1 enhanced, the malignant phenotype of LUAD cells in vitro. Consistently, cells with flotillin-1 knockdown formed smaller tumors in nude mice than cells transfected with the empty vector. Furthermore, the control group demonstrated significantly more tumorigenic effects compared to the flotillin-1-silenced group in the xenograft model of LUAD. In all, there draws a conclusion that flotillin-1 is a tumorigenic protein that plays an important role in promoting the proliferation and tumorigenicity of LUAD, suggesting that flotillin-1 may represent a novel the therapeutic target to LUAD.

miR-124-3p acts as a potential marker and suppresses tumor growth in gastric cancer

miR-124-3p has been implicated in a variety of cancers. The purpose of the present study was to investigate the expression, prognostic roles and functions of miR-124-3p in gastric cancer. Functional studies indicated that ectopic overexpression of miR-124-3p in gastric cancer cells suppressed cell viability and plate colony formation in vitro and tumor growth in vivo. In situ hybridization analysis demonstrated that decreased expression of miR-124-3p was associated with clinical stage and lymph node metastasis, as well as shorter overall survival and disease-free survival rates. Furthermore, it was observed that miR-124-3p repressed the carcinogenesis of gastric cancer by targeting Ras-related C3 botulinum toxin substrate 1 (Rac1) and specificity protein 1 (SP1). Collectively, these results indicate a potential underlying mechanism for the regulation of gastric cancer by miR-124-3p involving targeting of Rac1 and SP1. Thus, miR-124-3p may be an independent indicator of survival and treatment strategy for patients with gastric cancer.

Serum human epididymis secretory protein 4 as a potential biomarker of renal fibrosis in kidney transplantation recipients

BACKGROUND

Renal fibrosis remains an important cause of kidney allograft failure. The objective of this study was to evaluate the performance of serum human epididymis secretory protein 4 (HE4) as a biomarker for renal fibrosis in kidney transplant recipients.

METHODS

A total of 103 kidney transplantation patients were enrolled in this study, and serum HE4 concentrations were detected using the chemiluminescent microparticle immunoassay. Renal biopsy was carried out, and histological findings were assessed by immunohistochemistry.

RESULTS

Median serum HE4 concentrations were significantly increased in kidney transplant recipients (186.2 pmol/l, interquartile range [IQR] 125.6-300.2) compared with control subjects (34.3 pmol/l, IQR 30.4-42.3, p < 0.0001). Meanwhile, serum HE4 concentrations were significantly increased along with disease severity (p < 0.0001). In addition, we found serum HE4 concentrations to be strongly correlated with the severity of fibrosis (IF/TA 0, 1, 2, and 3: 114.3, 179.0, 197.8, and 467.8 pmol/l, respectively; p < 0.0001) and serum HE4 concentrations significantly correlated with HE4 tissue expression concentrations in renal biopsy.

CONCLUSIONS

Serum HE4 was increased in kidney transplant recipients with decreased kidney function and renal fibrosis and was correlated with the severity of the disease, suggesting that HE4 has the potential to be used as a novel clinical biomarker for evaluating kidney function and predicting renal fibrosis in kidney transplant recipients.

Flotillins Regulate Focal Adhesions by Interacting with α-Actinin and by Influencing the Activation of Focal Adhesion Kinase

Cell–matrix adhesion and cell migration are physiologically important processes that also play a major role in cancer spreading. In cultured cells, matrix adhesion depends on integrin-containing contacts such as focal adhesions. Flotillin-1 and flotillin-2 are frequently overexpressed in cancers and are associated with poor survival. Our previous studies have revealed a role for flotillin-2 in cell–matrix adhesion and in the regulation of the actin cytoskeleton. We here show that flotillins are important for cell migration in a wound healing assay and influence the morphology and dynamics of focal adhesions. Furthermore, anchorage-independent growth in soft agar is enhanced by flotillins. In the absence of flotillins, especially flotillin-2, phosphorylation of focal adhesion kinase and extracellularly regulated kinase is diminished. Flotillins interact with α-actinin, a major regulator of focal adhesion dynamics. These findings are important for understanding the molecular mechanisms of how flotillin overexpression in cancers may affect cell migration and, especially, enhance metastasis formation.

LncRNA MALAT1 promotes tumor growth and metastasis by targeting miR-124/foxq1 in bladder transitional cell carcinoma (BTCC)

Mounting evidence shows that the long non-coding RNA MALAT1 plays a pivotal role in tumorigenesis and metastasis, but the functional significance of MALAT1 in bladder transitional cell carcinoma (BTCC) remains unclear. MALAT1 expression was measured in 56 BTCC patients and 2 BTCC cell lines by real-time PCR. The effects of MALAT1 on BTCC cells were investigated by over-expression approaches in vitro and in vivo. Insights of the mechanism of competitive endogenous RNAs (ceRNAs) were validated through bioinformatic analysis and luciferase assay. MALAT1 up-regulation positively correlated with advanced clinical pathological stage and shorter survival of BTCC patients. Furthermore, MALAT1 over-expression promoted proliferation, migration and invasion of BTCC cells in vitro and in vivo. Particularly, MALAT1 may function as a ceRNA to sponge miR-124, thus modulating the derepression of foxq1, miR-124 target gene, in post-transcriptional levels. The positive MALAT1/foxq1 interaction was confirmed by bivariate correlation analysis, and this positive correlation was of great significance in BTCC tumor growth and metastasis, also accompanied by EMT changes. Overall, this ceRNA regulatory network concerning MALAT1 and the positive MALAT1/foxq1 correlation benefit a better understanding of BTCC pathogenesis and promote the feasibility of lncRNA-directed therapy against this disease.

Circulating microRNA124-3p, microRNA9-3p and microRNA196b-5p may be potential signatures for differential diagnosis of thyroid nodules

It is important to develop an effective auxiliary approach to distinguish papillary thyroid carcinoma (PTC) from benign nodules because a considerable proportion cannot be identified by fine-needle aspiration cytology at present, resulting in unnecessary thyroidectomy. Circulating miRNAs are potential biomarkers for differential diagnosis of tumors. We aimed to investigate the dysregulation of circulating miRNAs in PTC and evaluate the diagnostic value for differentiation of PTC from benign nodules. We first assessed the expression of miRNAs in patients with PTC, patients with benign nodules and healthy controls using a miRCURY LNA Array (n = 3 for each group). Expression of circulating miR-124-3p, miR-9-3p and miR-5691 was significantly up-regulated, while miR-4701 and miR-196b-5p were down-regulated in PTC patients. The dysregulation of miR-124-3p, miR-9-3p, miR-4701 and miR-196b-5p was further validated by qRT-PCR in fifty participants from each group. The expression of circulating miR-124-3p and miR-9-3p was significantly up-regulated in PTC patients. Both miR-124-3p and miR-9-3p could distinguish PTC from benign nodules with high sensitivity and specificity. There were no significant differences in the expression of circulating miR-4701 and miR-196b-5p between PTC patients and healthy controls. Nevertheless, patients with benign nodules showed a higher level of miR-196b-5p compared with that of PTC patients and healthy controls. ROC analysis indicated that miR-196b-5p had a good diagnostic value for differentiation of benign nodules from PTC. Our study suggested that miR-124-3p, miR-9-3p and miR-196b-5p may be potential signatures for differential diagnosis of thyroid nodules in eastern coastal areas of China.

microRNA-124 inhibits bone metastasis of breast cancer by repressing Interleukin-11

Background

Most patients with breast cancer in advanced stages of the disease suffer from bone metastases which lead to fractures and nerve compression syndromes. microRNA dysregulation is an important event in the metastases of breast cancer to bone. microRNA-124 (miR-124) has been proved to inhibit cancer progression, whereas its effect on bone metastases of breast cancer has not been reported. Therefore, this study aimed to investigate the role and underlying mechanism of miR-124 in bone metastases of breast cancer.

Methods

In situ hybridization (ISH) was used to detect the expression of miR-124 in breast cancer tissues and bone metastatic tissues. Ventricle injection model was constructed to explore the effect of miR-124 on bone metastasis in vivo. The function of cancer cell derived miR-124 in the differentiation of osteoclast progenitor cells was verified in vitro. Dual-luciferase reporter assay was conducted to confirm Interleukin-11 (IL-11) as a miR-124 target. The involvement of miR-124/IL-11 in the prognosis of breast cancer patients with bone metastasis was determined by Kaplan-Meier analysis.

Results

Herein, we found that miR-124 was significantly reduced in metastatic bone tissues from breast cancers. Down-regulation of miR-124 was associated with aggressive clinical characteristics and shorter bone metastasis-free survival and overall survival. Restoration of miR-124 suppressed, while inhibition of miR-124 promoted the bone metastasis of breast cancer cells in vivo. At the cellular level, gain of function and loss-of function assays indicated that cancer cell-derived miR-124 inhibited the survival and differentiation of osteoclast progenitor cells. At the molecular level, we demonstrated that IL-11 partially mediated osteoclastogenesis suppression by miR-124 using in vitro and in vivo assays. Furthermore, IL-11 levels were inversely correlated with miR-124, and up-regulation IL-11 in bone metastases was associated with a poor prognosis.

Conclusions

Thus, the identification of a dysregulated miR-124/IL-11 axis helps elucidate mechanisms of breast cancer metastases to bone, uncovers new prognostic markers, and facilitates the development of novel therapeutic targets to treat and even prevent bone metastases of breast cancer.

Electronic supplementary material

The online version of this article (10.1186/s12943-017-0746-0) contains supplementary material, which is available to authorized users.

Flotillin1 promotes EMT of human small cell lung cancer via TGF-β signaling pathway

Objective

Small cell lung carcinoma (SCLC) is considered one of the most aggressive types of lung cancer due to its rapid growth and early metastasis. No tumor markers or therapeutic targets have been demonstrated to be specific or effective in SCLC to date. This study aims to evaluate the potential of Flotillin1 (Flot1) as a target of SCLC treatment.

Methods

Flot1 expression level in the tissue of SCLC and other tissue of lung disease was detected using immunohistochemical staining. Transwell and Matrigel assays were employed to examine migration and invasion of cancer cells. Flow cytometry and xCELLigence system were used to evaluate cell apoptosis and cell viability, respectively. Expression levels of Flot1, epithelial-mesenchymal transition (EMT) marker E-cadherin, vimentin, cyclinD1, TGF-β-Smad2/3, and p-AKT were examined using Western blot. Furthermore, xenograft tumor in nude mice was used to evaluate the growth and metastasis of NCI-H446 cells in vivo.

Results

Our results demonstrated that Flot1 is highly expressed in SCLC samples and that its expression correlates strongly with clinical stage, distant metastasis, and poor survival. The knockdown of Flot1 decreased the growth, migration, and invasiveness of SCLC cells and reversed EMT phenotype in vitro and in vivo, while enhanced Flot1 expression exhibited the opposite behavior. Gene expression profile analysis demonstrated that Flot1-regulated genes frequently mapped to the AKT and TGF-β-Smad2/3 pathways. Our results further revealed that Flot1 affected the progression of SCLC via regulation of EMT progression.

Conclusions

These findings indicated an oncogenic role of Flot1 via promoting EMT in SCLC and suggested its potential as a tumor marker and prognostic indicator.

MicroRNA-124-3p directly targets PDCD6 to inhibit metastasis in breast cancer

Breast cancer (BC) is the leading cause of cancer-associated mortality among women worldwide, with a poor 5-year survival rate, particularly among patients with metastatic BC. Previous studies have indicated that the dysregulation of microRNAs (miRNAs/miRs) is associated with carcinogenesis and metastasis. Thus, investigating the underlying molecular mechanisms by which miRNAs mediate their effects may aid in the improvement of BC treatment. In the present study, reverse transcription-quantitative polymerase chain reaction analyses were performed to investigate miR-124-3p expression in BC tissues. The expression of miR-124-3p was significantly decreased in primary BC tissues compared with that in adjacent non-tumor tissues. Downregulated miR-124-3p was correlated with lymph node metastasis and a low overall survival time. Wound-healing and Transwell assays revealed that MDA-MB-231 and MCF-7 cell motility was inhibited by miR-124-3p, but was promoted by a miR-124-3p inhibitor. Overexpression of miR-124-3p increased levels of E-cadherin, and decreased levels of N-cadherin and Vimentin, indicating that miR-124-3p inhibits the epithelial-mesenchymal transition. In addition, a bioinformatics analysis and subsequent in vitro experiments identified programmed cell death protein 6 (PDCD6) as a direct target of miR-124-3p. Restoration of PDCD6 expression impaired the metastasis inhibitor role of miR-124-3p by promoting cell invasion. Furthermore, the expression of miR-124-3p was inversely associated with PDCD6 mRNA levels in clinical breast tumors. Taken together, these data suggest that miR-124-3p inhibits tumor metastasis by inhibiting PDCD6 expression, and that the miR-124-3p/PDCD6 signaling axis may be a potential target for novel treatments in patients with advanced BC.